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Bluetooth antenna?

I've just been doing some power consumption tests on the bluetooth module. Giving it 3.8v and shoving some Radio Paradise through it from my phone I measured it at 20mA. It seemed to power down when I turned the voltage down below 2.6 or so, and seems happy at both USB and 18650 level voltages (almost as though it was made for 'em=)
Good stuff. I haven't tried to find the upper voltage limit because I don't want to kill it. I do have 2 more on order though..=)
 
I've ordered the Bluetooth thing and the amp, if they work like yours it's a sensational fiver! I may even build a case. What's the 18650 you talk about, is it that battery pack?
 
Nice one Steve, I'm sure you'll be impressed. The battery pack is just an Anker USB battery pack meant for charging mobile phones etc. I'm pretty sure it contains several 18650's, which are rechargeable lithium ion batteries that look a bit like large AA cells. 18650's are used in some torches, vape things, laptop battery packs, power tools and teslas=)
That amp seems to prefer closer to 12v rather than 5v, so you might consider a usb step up thing too if you want to make it all usb battery pack powered.

18650's are like this: https://www.ebay.co.uk/itm/USB-Booster-5V-to-9V-12V-DC-Circular-Hole-Charger-Tester-Router-Power-UK/312724431487?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

Or you could just use a 12v wall wart power brick thing to power the amp of course.
 
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Thanks Dik, that makes a lot of sense. As you say the initial plan to get it running will be to run the BT device from a USB charger and the amp can get a 12V supply from one of the various wallwart things I have lying about, as we all do. In fact I have one that's a little "hot", it delivers about 15V off load and it has fried a 12V chipamp in the past. Given the TDA9297 (or whichever one it is) runs 6V to 18V, it will be fine at 15V and the extra headroom will do no harm. Longer term I may do some tinkering to generate a regulated supply or step up a USB as you say to run the amp. Probably the former would be better, at 2 x 15W a USB will struggle. 5V, 2 x15W, 6A RMS from a USB? Hmm, don't think so.

I think this is going to be good fun. Thanks for the tip.
 
Fun is exactly what they are. Cheap as chips and great vfm to play with=)

I just plugged a usb power meter between the power bank and the 12v stepup cable. Amp "on" but no signal the meter shows it's drawing about 0.03 amps, and when playing at my usual low background listening level it jumps to a massive 0.07 amps or so. Winding the volume up to louder than I wanted pushed it to around 0.15 amps.
No idea on the accuracy of this test, but it does give an indication of the sort of juice it's using. The power bank powers it for many days. I usually just top it back up when ever it's not being used, I haven't done a "run it flat consumption test yet.

I do listen at low volumes, small flat, thin walls, and tinitus to worry about so I don't need huge gobs of power=)

Turning the volume knob up with no music playing does give some noise, but that's at "Turn it down you git" neighbour annoying levels. I'm assuming most of that noise is from the voltage boost thing. I'll have to drag out a 12v Sealed Lead acid battery to try one day. Might even try getting all sciency and plug an oscilloscope and sig gen into it all and pretend I know what I'm doing=) Fun!
 
Dik Dolan said:
Fun is exactly what they are. Cheap as chips and great vfm to play with=)

I just plugged a usb power meter between the power bank and the 12v stepup cable. Amp "on" but no signal the meter shows it's drawing about 0.03 amps, and when playing at my usual low background listening level it jumps to a massive 0.07 amps or so. Winding the volume up to louder than I wanted pushed it to around 0.15 amps.
No idea on the accuracy of this test, but it does give an indication of the sort of juice it's using. The power bank powers it for many days. I usually just top it back up when ever it's not being used, I haven't done a "run it flat consumption test yet.

I do listen at low volumes, small flat, thin walls, and tinitus to worry about so I don't need huge gobs of power=)

Turning the volume knob up with no music playing does give some noise, but that's at "Turn it down you git" neighbour annoying levels. I'm assuming most of that noise is from the voltage boost thing. I'll have to drag out a 12v Sealed Lead acid battery to try one day. Might even try getting all sciency and plug an oscilloscope and sig gen into it all and pretend I know what I'm doing=) Fun!
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A consumption of 1.8W average is tiny. That's a realistic figure too, as it's straightforward DC voltage x current, Ohm's Law stuff. Peaks, who knows? Maybe 4 or 5 W in peaks. When I have run chipamps before they perform MUCH better when a SLA battery or similar is put on them, I once ran an original T-amp from a battery booster pack propped up by a 12V x 1A wallwart and it was really very good indeed. I would have put it against decent budget hifi amps like the NAD 3020 and the Rotel 820 and it would not have been out of place. I'm looking forward to seeing how this one performs, I might even try a pile of them in an active experiment. At the money, what's not to like?
 
I'll definitely have to drag out the 12v battery "soon" to try. I also have 6 of the 18650 cells I "rescued" from my old netbook battery pack I can try to make up to a 12v-ish psu, 3 in series should give 11 or 12 volts depending on their charge level. I am trying to avoid my old audiophile urges to modify/tweak/foo it all with better capacitors, cables etc (for now!)

I may have missed something but my math said it was consuming more like 0.35 watts? The meter was measuring out from the battery bank, and before the step up to 12v so 5v x 0.07A. I'm fully prepared to doubt my figures though!

I hadn't listened to any music for around 5 years, then I got a smart phone last year, which lead to me getting a bluetooth sound bar speaker thing so I could have some background sounds while I played at building model kits in my kitchen.... which has lead to buying these bits and pieces. I still haven't tried turning my main hifi back on yet.... Now I'm beginning to feel scared it would be shown up=)
 
Dik Dolan said:
I'll definitely have to drag out the 12v battery "soon" to try. I also have 6 of the 18650 cells I "rescued" from my old netbook battery pack I can try to make up to a 12v-ish psu, 3 in series should give 11 or 12 volts depending on their charge level.
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Both good choices, go for it. They handle surges of current much better than the SMPS type solutions.

I may have missed something but my math said it was consuming more like 0.35 watts? The meter was measuring out from the battery bank, and before the step up to 12v so 5v x 0.07A. I'm fully prepared to doubt my figures though!
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No, you're right, I'd misunderstood. I thought you were measuring current at 12V. 0.07A at 5V really IS tiny, you must be listening VERY quietly as I always thought a rule of thumb was that a transistor radio was about 500mW.

I hadn't listened to any music for around 5 years, then I got a smart phone last year, which lead to me getting a bluetooth sound bar speaker thing so I could have some background sounds while I played at building model kits in my kitchen.... which has lead to buying these bits and pieces. I still haven't tried turning my main hifi back on yet.... Now I'm beginning to feel scared it would be shown up=)
Click to expand...
Anything that gets you listening to music and enjoying it is a win. It's astonishing what you can do now for next to nothing. I really wouldn't like to put a phone, BT link, and chipamp against budget gear from the 80s, the Dual/NAD/Wharfedale Diamonds of this world. I certainly wouldn't at the price. I just wish that I could have had a chipamp for a couple of quid back then. A set of bookshelf speakers and I would have been up and running.
 
Thanks for the encouragement=)

I DO listen quietly. Always have, really. Sudden loud noises scare the crap out of me. Especially if it's a neighbour hammering on the wall to get me to turn it down=)
I've been googling "charging 18650 cells" and watching a few videos to try to learn more about basic do's and dont's. Some of the "Dont try this at home" versions are scary! So far I've been using my bench psu to charge them using it's cv/cc features which works fine if a bit slow doing one at a time using croc clips and magnets but now I have some of these on the way at 39.5p each if I buy 10. http://rover.ebay.com/rover/1/710-5...0001&campid=5338728743&icep_item=263021370872

Battery holders are similar prices too, a pack of 10 for £2.60. Astonishing vfm again! I'm having great fun playing with all this stuff for pocket money prices. It's got me active and thinking a bit again which has to be good... Now if I can just get these batteries charged without letting the smoke out it would be golden=)
 
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Any idea of range/signal strength?
How about feeding chip amp/speakers 2 rooms/30 feet/two stud walls away?
 
I'll test that, as much as I can in my rabbit hutch flat.. give me a sec.
Back.
Ok, I took my phone into the kitchen, which is on the opposite side of my flat- one brick wall, one narrow hallway, one stud wall and 2 doors away. Less than 30feet I'm sure, but it worked fine. I also tried up the stairs to my bathroom (above the kitchen, so a bit further) and it still seemed fine. I have no way of measuring signal strength, but got no loss of signal or drop outs that I could hear.
I have no way of testing further distances without going outside, but it's scary out there and unless I left my phone and carried the battery pack, amp and speakers outside.... or left my phone on the street and ran back inside.... =)
So.. in conclusion, I couldn't get it to drop out in the confines of my flat.
 
LLLLOL
Way beyond the call of duty, and an impressive range for something costing nit-poop.

Many thanks.
 
No problem=) Thanks for reminding me to try it.
One problem I've come across is because it consumes so little power (20mA or so) plugging it into a battery USB powerbank on it's own isn't using enough power to keep the battery bank from turning off. The Anker I showed in the pic earlier has 2 usb outlets, so having the amp in one (which is enough to keep it on) and the BT module in the other and all's good. I could just use a single 18650 battery in a single battery holder and add a switch to power it on it's own if/when I ever get around to trying different psu's for the amp.

I did come across this handy looking little project while googling how to stop powerbanks from self powering down when they arent being used enough to keep em awake. https://www.instructables.com/id/Current-Pulsing-Keeps-Power-Bank-Active/ I might try that, if I ever manage to find that 555 chip I know I have somewhere...

Oh, I also forgot to mention it has the brightest blue LED on it that blinks away all the time it's playing. But that's ok the chip amp has a matching blindingly bright blue LED that stays on all the time it's powered up.... all the more incentive to make me want to fit them in a decent little case "soon" =)
 
I'll get some modules and have a play.
If the BT module can be run directly from the same 12V wall wart they will be an answer to a friend's prayers - amp and BT module in one box for each speaker, using one channel only from each amp. If it has to have a small drop-down circuit for the BT I will curse, but that is hardly rocket science.
 
The ebay blurb voltage specs for the one I got says 3.7 - 5v, so I2v might let the smoke out. Maybe a buck converter thing in front of it would be safer?
Here's a listing for buying them in multiples of 10 for those "just in case I need spares" tests=) I'm tempted myself even though I already have 2 on the way... I like having spares.

https://www.ebay.co.uk/itm/VHM-314-Bluetooth-Receiver-Board-Module-Mp3-Lossless-Decoder-Board-Replacement/123955755141?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

Another thought-
I'm pretty sure my nokia 1 phone can only connect to one bluthooth thing at a time. So connecting to 2 at once wouldn't be possible. I have no idea if other phones or sources can connect to multiple devices though. I'm very new at all this mobile phone/BT streaming malarky=)
 
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Great minds..……………..
I just ordered enough and spare of a £1 DC-DC motor speed/voltage controller - FAR cheaper than making from scratch - lunacy!!!

As ever, the case for this is going to cost 3-5 times what the contents cost...……………...
 
A voltage controller is a good idea. My BT and amp isn't here yet.

I teckon I can get it in a case for very little by virtue of not buying one. I think it's going to go in something stupid like a yogurt pot. Because I can, so why not? I've heard of people putting them in cig packets, but I don't smoke. I shall rummage around in the Dead Kit Box or use some redundant food packaging. I have just the thing...a salad bowl with a screw cap. Watch this space.
 
stevec67 said:
I teckon I can get it in a case for very little by virtue of not buying one. I think it's going to go in something stupid like a yogurt pot. Because I can, so why not? I've heard of people putting them in cig packets, but I don't smoke. I shall rummage around in the Dead Kit Box or use some redundant food packaging. I have just the thing...a salad bowl with a screw cap. Watch this space.
Click to expand...

VERY elegant LLLLLLOL

The limitation will be the heatsink for the amp', not ideally suited for yoghourt pot mounting.
 
I like your thinking there Steve=)
Here's my idea. Of course it didn't fit.
marmite amp by dik_dolan, on Flickr

I just remembered that I have a box of 1000 wooden coffee stirrers somewhere that I bought ages ago to make wooden frames to hold model kit assemblies-engines, chassis etc. while I worked on 'em. I suppose I could make a small box any size/shape I wanted out of them. Hmmmm.
 
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